Method and apparatus for cutting roller type chain

ABSTRACT

ROLLER TYPE CHAIN IS CUT INTO A SELECTED NUMBER OF SHORTER CHAINS OF SELECTED LENGTH UNDER THE CONTROL OF AN ELECTRONIC SYSTEM WHICH EFFECTS FEEDING THE UNCUT CHAIN ABOUT A SPROCKET AT A WORK STATION AND PUNCHING AT LEAST ONE ROLLER PIN FROM A LINK AT THE WORK STATION AFTER EACH FEEDING OPERATION. THE SPROCKET AT THE WORK STATION FUNCTIONS IN A MULTIPLE CAPACITY IN THAT IT IS DRIVEN TO PULL THE UNCUT CHAIN FROM A SUPPLY REEL, ACCURATELY INDEXED TO POSITION A SELECTED LINK AT THE WORK STATION AND PROVIDES AT LEAST PART OF AN ANVIL DURING THE PUNCHING OPERATION.

[ June 28, 1974 United States Patent [191 OCallaghan 3,553,960 l/l97l Ellefson..................................59/1l 3 640 I64 2/l972 Crafford et al. 59/ll METHOD AND APPARATUS FOR CUTTING ROLLER-TYPE CHAIN [76] Inventor: Jerome J. OCallaghan, W. 125 S.

Primary E.\"aminerCharleS W. Lanham Assistant Examiner-James R. Duzan 6493 Whittier Ter., Hales Corners, Wis. 53715 Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santeen, Steadman, Chiara & Simpson [22] Filed: Oct. 25, 1972 Appl. No.: 300,488

ABSTRACT Roller type chain is cut into a selected number of shorter chains of selected length under the control of an electronic system which effects feeding the uncut chain about a sprocket at a work station and punching 2 7 0 2 4 99 51 RQW 24 M3 9 n9 2 m 7 M v w m mmh N .r mm m L mf C .M .w UhF at least one roller pin from a link at the work station after each feeding operation. The sprocket at the work S T. N m M B MM 9 on e u N U Q U station functions in a multiple capacity in that it is driven to pull the uncut chain from a supply reel, ac-

curately indexed to position a selected link at the work station and provides at least part of an anvil during the punching operation mmm m Wm m r n n e U "S b u n n.. "no L m mhm tm a i QPAS 345 6666 9999 NH 0765 601'] 0344 ,A 395a! 0938 OOIl-l 18 Claims, 9 Drawing Figures PATENTEWW 28. m4.

SHEET 2 OF 6 METHOD AND APPARATUS FOR CUTTING ROLLER-TYPE CHAIN BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to cutting roller type chain, and is more particularly concerned with auromatically cutting such a chain into a selected number of shorter chains of selected length automatically in response to control effected by an electronic control system.

2. Description of the Prior Art In the chain art the term cutting" is not used in the classical sense to mean shearing of material, but more specifically defines a separation which includes the removal of a pin to disengage the outboard pin link plates from at least one end of a roller link. In cutting roller chain having riveted or spun ends of the pins, the most simple technique for cutting the chain, one secures the chain in a vice or the like and removes the pin by hand with a punch and hammer. This technique, while adequate for a single cutting operation, has the disadvantages of giving rise to the possibility of bent links and being time consuming when a great number of cuts are to be made.

Another technique for cutting chains involves the positioning of a link to be cut in an anvil-type jig which is positioned belowa punch which employs the mechanical advantage of a hand operated long lever arm for effecting the punching operation. Again, this technique, while adequate for a single or small number of cuts, is to time consuming and to tiring for an operator when a great number of cuts are to be made. However, this is probably the most widely used chain cutting technique today.

The former type of pin removal technique may b found, for example, in U.S. Pat. No. 3,464,201 to J. W. Ehlen which discloses a method of removing a pin from link chain devices, the removal of a pin from a link chain of a chain saw being particularly disclosed. The latter technique is exemplified in U.S. Pat. No. 3,135,141 to W. H. Aitken, which is also directed to techniques for removing pins from chain saw chains.

The art also recognizes elimination of the aforementioned fatiguing hand operation as disclosed in, for example, U.S. Pat. No. 3,553,960 to C. C. Ellefson, wherein a fluid operated ram is employed for punching the pins of a roller chain. Although some of the hand operation has been eliminated in pin knockout devices of this type, the chain must still be manually handled, i.e., fed, positioned, separated parts accumulated, etc.

SUMMARY OF THE INVENTION The primary object of the present invention is to provide a method and apparatus for automatically cutting a supply chain into a selected number of shorter chains of selected length automatically without the intervention of an operator.

Another object of the invention is to provide pretensioning of chain as it is fed to be cut.

Anothe object of the invention is to detect when the chain supply becomes exhausted and to automatically interrupt the chain cutting cycle in response to the detection of such exhaustion.

A chain cutting method, according to the present invention, includes the steps of feeding a selected length of chain from a chain supply to a work station, punching at least one pin from the chain to separate the selected length from the supply chain and repeating the feeding and punching steps a desired number of times to obtain a desired number of shorter chains. The chain may be prestressed during the feeding operation by the interposition of a prestressing mechanism between the supply spool and the punching station. In order to prevent a short terminal length of chain from being precessed and possibly having an error in chain length for each supply spool, means are provided for sensing the passage of the terminal end of the chain from the supply spool for terminating the automatic cutting operation.

The chain is pulled from the supply spool by a sprocket at the punching station which functions in several other capacities including accurate alignment of the chain relative to the punch or punches in cooperation with the movement of the punch holer and serving as at least part of an anvil during the punching operation. It should be noted that the punching operation may employ a pair of punches to remove both pins of a pin link at which time the sprocket serves as an anvil beneath the upper link plates, and single punch may be employed to remove a single pin during which operation an auxiliary anvil is provided below the lower connecting links and having a recess for receiving the punched pin. In the latter case, the punched pin may be completely removed or left attached to one of the pin plates. In either case an auxiliary guide positions the chain on the sprocket.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention, its organization, construction and operation will be best understood from the following detailed description taken in conjunction with the accompanying drawings, on which:

FIG. I is a top plan view of a chain cutting machine constructed in accordance with the principles of the present invention;

FIG. 2 is an elevational view, partially in fragmentary section, showing the feed sprocket and its support;

FIG. 3 is a fragmentary view of a roller chain entrained about the feed roller and showing the relationship of the pin punches with respect to the pins;

FIG. 4 illustrates a prestressing apparatus which may be interposed in the chain feed illustrated in FIG. 1;

FIG. 5 is a side elevational view, shown partially in section, or the work or punching station and associated position and alignment apparatus;

FIG. 6 is'a front elevational view, shown partially in section looking into a punching station;

FIG. 7 illustrates the apparatus for sensing the exhaustion of chain supply;

FIG. 8 is a block diagram of the electronic control apparatus which controls and monitors the automatic chain cutting operation; and

FIG. 9 is an exemplary mechanical flow chart of the operation of the chain cutting machine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a chain cutting machine is generally referenced 10 and comprises a table 11 which may be mounted on legs (not shown). The table 11 carries a chain supply spool 12 mounted for rotation thereon,

a punching station 13, a control station 14 and a chian feed path 15.

A chain 16 is pulled from the supply reel 12 and about a plurality of spools 17-26 by a sprocket 27 which is driven by a motor 28 via a belt 29. The spools 18-26 fonn a variable length service loop in the chain which aides in overcoming the inertia of the supply reel '12 in feeding the chain. The spools 21, 23 and 25 are each mounted on a platform 30 having wheels 31 which run between guides 32 and are counterweighted near the rear edge 34 of the table by way of a strand, referenced 35 attached to a weight (not shown) and trained over a pulley 36. This structure is quite similar to that illustrated for the spool 17 in FIG. 7, in which case the strand 35 would be a chain and the pulley 36 would be a sprocket.

Referring to FIG. 7, the spool 17 and its associated apparatus for detecting exhaustion of chain from the reel 12 is illustrated. The spool 17 is rotatably mounted on a shaft 35 which is in turn mounted on a slide 38. The slide 38 is movable in a passageway 39 and is biased toward the right by a weight 40. The weight 40 is connected to the slide 38 by means of a chain 41 which is trained about a sprocket 42. The sprocket 42 is mounted for rotation between a pair of plates 43 one of which includes an L-shaped mounting bracket 44 which carries a switch 45 having a roller type actuator 46 which extends through an aperture 47 in the lower wall 48 of the passageway 39 in an interference relationship with the slide 38. The slide 38 has an inclined leading surface 49 which acts as a cam for the actuator 46. Therefore, as the chain is exhausted from the reel 12 and does not oppose the force of the weight 40, the slide 38 is moved toward the right to operate the switch 45. The switch 45 is connected in the circuit for controlling the energization of the motor 28 and prevents energization of the motor when the slide 38 depresses the actuator 46.

Prestressing Feature Referring to FIGS. 1 and 4, the apparatus of FIG. may be interposed in the chain feed path at, forexample, the point 50, this point being referenced 50a and 50b in FIG. 4. At this location, the chain 16 is entrained about three sprockets 51, 52 and 53. The sprocket 51 is carried for rotation by a shaft 54 and the sprocket 53 is carried for rotation by a shaft 55. The shaft 54 and the shaft 55 carry respective gears 56 and 58 at the opposite ends thereof which are engaged with a gear 57 driven by a motor 59. The motor 59 is driven in a direction to feed chain toward the work station 13. During the feeding operation the sprocket 52 may be displaced transversely of the general direction of chain travel as indicated by the double headed arrow 60 to increase or decrease the length of the path and pretension the chain in accordance therewith due to the constant drive provided by the motor 59. The Control Station 14 The control station 14 may be constructed in accordance with particular chain cutting applications. In an embodiment of the apparatus constructed in accordance with principles of the present invention, however, a SLO-SYN high speed indexer as manufactured by The Superior Electric Co., Bristol, Conn., was employed.

The indexer employed is structurally and functionally represented in FIG. 8 wherein 61 and 62 represent the number of links and a factor multiplier for the selected chain. The length of a chain is defined by the number of links or pitches of the chain; therefore at 61 the desired length to be cut from the supply chain is set by way of selection switches. At 62 the factor representing the pitch of the chain is set resulting in a product at 63. At 75 the number of chains to be cut may be set. A clock 64 gates the digits into a storage resister at 65. The information as to the selected length of chain and the number of chains to be cut is therefore stored in the register 65.

A run/stop control 66 includes several inputs as evident in the drawing and as readily apparent from the foregoing description. For example, an end of chain control 67 corresponds to the operation of the switch 45 in FIGS. 1 and 7. An emergency stop control 68 may, of course, be a simple on off switch as is provided on most all apparatus for safety reasons. An output from the program sequence control 69 is employed for effecting a running condition during the cutting operation and for stopping the machine at the end of the cutting operation.

' The run/stop control 66 controls a program clock 70 which strobes a program generator 71 to feed data to the program sequence control 69 for effecting indexing of the control system itself and of the chain cutting apparatus.

One indexing signal is the punch command 72 which operates a punch driver which, in turn, operates a reciprocal ram (indicated by the double headed arrow 82 in FIGS. 5 and 6).

A second indexing command is issued to a strand count drive 74 which in turn operates a strand counter 75 to generate a stop signal for the run/stop control 66 when a predetermined number of strands have been counted.

An index command 76 and a reset command 77 are provided for controlling the operation of the motor drive circuit 78 which fumishes drive pulses to the motor. The particular motor utilized can be controlled by the motor drive circuit 78 to move l/20O revolution per pulse so that the accuracy of positioning a selected connecting link below the punch is very good.

A data transfer command 79, in conjunction with the count insertion command 80 causes the data stored in the register 65 to be transferred by way of the gates 81 to the motor drive control circuit 78. This control effects the feeding of the selected number of links past the punch a selected number of times.

Although the control system and the particular motor utilized in feeding and registering the chain is quite accurate, a less expensive system with a mechanical registration feature may be employed as discussed below with respect to FIG. 5.

The Punching Station 13 Although the feed sprocket 27 is located at the punching station, its mounting will be discussed in detail with respect to FIG. 2 in that the mounting of the sprocket includes a unique feature.

Referring first to FIG. 3, the supply chain 16 is illustrated as engaged with and entrained about the sprocket'27 as it appears at the punching station 13. The chain 16 includes a plurality of spaced pairs of roller link plates 83 having pairs of rollers 84 located therebetween by means of pins 85 adjacent roller link plates, for example 83a, 83b and 83c, 83d, are bridged by respective pin link plates 86, 87 which, in this particular example, is the point selected for the chain to be cut. Respective pins a, 8511 which have their ends riveted or spun to secure the pin links and roller links have position thereabove respective punches 88 and 89. With the chain held stationary on the sprocket and both punches 88, 89 moving downwardly, the pin link plate 87 will be separated from the pins 85a, 85b while the pin link plate 86 remains connected to the pins. Upon withdrawal of the punches 88, 89, the chain has been cut and may be accumulated in a first bin, the sep arate connecting links 87 may be collected in a second bin and the links 86 with the pins 88, 89 connected thereto may be collected in a third bin. It should be noted that the connecting links and pins are reusable and that there is therefore no scrap or waste. For example, the previously cut end of the chain and the end just cut may be connected with the accumulated connecting links and pins to form endless chain.

If one of the punches 88, 89 is omitted, for example the punch 88, the connecting links 86 and 87 remain with the left hand section of chain ready to receive the roller end of another roller link, perhaps the previously cut end of the left hand chain section. Also, if the stroke of the punch 89 is limited to stop at the upper surface of the connecting link 86, the pin 85b also remains connected to the left hand chain section ready for reuse when the chain is connected to another roller link.

Referring to FIGS. 5 and 6, the punching station 13 also includes a reciprocating ram, symbolically referenced 82 which may be mounted above the table on a mount 90 (partially illustrated in FIG. 5). The ram 82 includes an extensible member 91 which is connected at 92 to a punch holder 93 which holds the punches 88, 89. The feed sprocket 27 is mounted above the table by means of mounting apparatus 94 (see FIG. 2) and operates to position the chain 16 below the punches 88, 89.

The punching station 13 includes a shaped member 95 having a step forward end 96 conforming to the shape of the chain about the sprocket. The member 95 is urged toward the chain by means of a spring biasing arrangement 98 mounted within a channel 97 of the mount 90 for the ram. A screw 99 renders the bias adjustable. The member 95 includes a slot 100 extending longitudinally thereof to an aperture 101. Upon retraction of the punches, an air jet 102 is effective to blow the upper pin link plate through the slot 100 to the ap-' erture 101 where it drops for collection in an appropriate bin via a passageway created by apertures or cut outs 103, 105 in a pair of stacked plates 104, 106, respectively. The last mentioned plate is carried on another plate 107 which, in turn, is carried on a base plate 108. The plate 107 includes an aperture 109 and the base plate 108 includes an aperture 110 which form a passageway for the lower pin link assembly including the pins to drop into an appropriate collecting bin. The path of travel of the upper plate to a bin 111 is indicated by the arrow path 112 and the path for the pin link plate pin assemblies to a bin 113 is indicated by the arrow path 114.

Of particular interest in FIG. 5 is an alignment pin 115 carried by an extension 116 of the punch holder 93. The pin 115 may be advantageously utilized to pass between adjacent teeth of the sprocket 27 to accurately align and fix the sprocket with respect to the punches and therefore accurately align and fix the chain for cutting. With this technique, a less expensive control sys- 6 tern may be utilized for feeding and positioning the chain.

A pair of electrical contacts for connection in the motor control circuit may be operated by the pin 115 to prevent operation of the motor 28 during a punching operation. In FIG. 5 such contacts are illustrated as a pair of normally closed contacts 117 (shown operated); however, normally opened contacts may be employed if motor control circuit design so indicates.

Referring to FIG. 6, a variation of the aforementioned control is illustrated as used with the aforementioned high speed indexer wherein mechanical registration is not utilized. In FIG. 6 a pin 118 is carried on an extension 119 of the punch holder 93. A switch 120 includes an actuator 121 which is operated by the pin 118 by way of an intermediate spring loaded actuator 122. Although the actuator 122 is not illustrated in detail, one skilled in the art will readily appreciate that it includes a cam follower which is spring loaded and urged into an interference relationship with the pin 118 and which responds to movement by the pin 118 to operate the switch actuator 121. The Feed Sprocket Mount 94 Referring to FIG. 2, the feed sprocket mount 94 includes a housing 123 having an upper wall 124 and a lower wall 125. An upper bearing 126 and a lower bearing 127 are secured in the housing 123 adjacent respective end walls 124, 125. A shaft 128 is carried by the bearings 126, 127 for rotation. At its lower end 129 the shaft 128 is connected for rotation by the motor 28, as indicated by the arrow 130. Adjacent its upper end 131 the shaft 128 carries the feed sprocket 27 mounted between a plate 132 and a plate 133. The plates 132 and 133 and the sprocket 27 are connected for mutual rotation by means of at least one pin 134 which extends through aligned apertures 135, 136, 137 of the plate 132, the sprocket 27 and the plate 133 respectively, the plate 133 being an integral flange of the shaft 128. In addition, a sleeve 138 covers the end 131 of the shaft 128 and is urged against the plate 132 by means of a washer 141 and a nut turned onto a threaded portion 139.

The housing 123 also encloses a sleeve 142 which bears against the lower face of the upper bearing 126 and the upper face of the lower bearing 127. The shaft 128 further includes a shoulder 143 which bears against the upper face of the upper bearing 126. The lower face of the lower bearing 127 bears against the lower end wall 125 of the housing 123. The end wall 125 is secured to the housing 123 by means of a plurality of screws 144 each having a threaded end 145 which engages a threaded bore 146 in the housing 123, an elongate portion 147, a flange 148 and a head 149. A spring 150 bears against the lower face of the end wall 125 and the flange 148 so that the sprocket 27 is spring mounted and permitted a predetermined amount of vertical movement during a punching operation. It should be particularly noted that the plate or flange 133 is spaced from the upper end wall 124. In one embodiment of the invention this spacing was provided as 0.010 inch. This spacing is provided so that an amount of axial movement of the sprocket is available from a free rotating position in order to take the thrust off the bearings and place it on the wall 124. Other arrangements would also be suitable e.g., a splined shaft with a flange supporting a bias spring.

Typical Cutting Operation Referring to FIG. 9, a flow chart is provided which sets forth a typical chain cutting operation. Assuming a starting point of feeding chain, chain is advanced or rejected by control unit indexing signals at 200 which causes the chain to be advanced by way of the feed sprocket 27 or rejected by way of the supply sensing apparatus 17, 45.

If the supply is exhausted at 201, a stop signal is issued to the control apparatus. If the chain supply is not exhausted the chain will advance and be stopped at 202 in response to indexing control signals. Upon stopping of the chain the fixed and movable spools 20-26 take up the chain between the punch station 13 and the reel 12 as indicated at 203 and the reel is stopped as indicated at 204.

During the chain takeup and reel stopping operations the link to be cut is positioned with respect to the punches and .the sprocket is locked during the downward stroke of the punch, these operations being indicated at 205, 206 and effected by the pins 115, 118 and the switches 117, 120 of FIGS. and 6 depending on the type of control unit employed.

During the continued downward movement of the punch the pins are punched as indicated at 207. This example assumes that both pins are punched whereby the two pins remain connected to the lower connecting link. The pin link assembly falls into bin 113 of FIG. 5 according to step 208, the cut chain is collected at 209 by way of a pivotal chute 160 in FIG. 1, the top pin link plate is ejected at 210 by the jet of air 102 in FIG. 5 and the connecting link plate is collected at 211 in bin 111 of FIG. 5. a

The upward movement of the punch also renders the previous locking of the sprocket and opening of the motor circuit ineffective and permits the initiation of a new cycle by indexing at the step 200 to advance a new length of chain.

Safety Features In addition to the aforementioned emergency stop and on/off type controls provided at the control station 14, other safety features may also be provided. For example, the motor 28 and its connection to the shaft 128 are located below the table and recessed away from working positions of an operator about the table. Also, a cover 161 is provided to enclose almost all other moving parts of the machine, such as the reel 12 and the spools 17-26. The cover 161 may advantageously be hinged at the rear of the table 11 and provided with a pair of handles I62, 163.

Although the invention has been described herein with reference to single strand chain, the invention is equally applicable to a wide variety of roller type chain including single pitch, double pitch and multi-strand roller chains, chain saw chains inverted tooth chains and the like. Also, many changes and modifications of the invention may become apparent to those skilled in the art .without departing from the spirit and scope of the invention. 1 therefore intend to include within the patent warranted hereon all such changes and modifications as may reasonably and properly be included within the scope of my contribution to the art.

I claim:

l. A method of cutting roller-type chain, comprising the steps of:

feeding a predetermined length of chain from a chain supply to a work station by engaging the chain and a sprocket and rotating the sprocket;

sequentially aligning the chain with the punch on the sprocket and punching at least one pin through the chain sufiiciently to separate the predetermined length from the supply; and repeating the feeding step and the sequential aligning and punching steps a predetermined number of times to produce a desired number of chains. 2. The method of claim 1, comprising the step of: pre-stressing the chain during the step of feeding.

3. The method of claim 1, wherein the step of feeding the chain further comprises the steps of:

sensing for the exhaustion of chain from the reel; and

terminating the step of feeding upon sensing the exhaustion of chain from the reel. 4. A method of separating a length of chain into shorter lengths of chain, comprising the steps of:

repetitively feeding links of a chain about a sprocket to define the desired shorter lengths of chain to a work station on the sprocket; cyclically punching at least one pin from each length defining link as it is positioned at the work station; and contemporaneously supporting the chain at the work station on the sprocket while feeding and punchmg. 5. The method of claim 4, wherein the step of feeding includes the step of:

repetitively energizing a feed motor coupled to the sprocket; and wherein the step of punching comprises the step of: v I inhibiting energization of the feed motor immediately in advance of each punching operation to prevent movement of the chain during punching. 6. The method of claim 4, comprising the step of: registering the length defining links with the punch prior to each punching operation. 7. The method of claim 4, further comprising the step of urging the chain against the sprocket.

8. Apparatus for cutting roller-type chain from a supply of chain comprising:

punching means operable to punch at least one pin of a connecting link a sufficient distance to separate the chain; feeding means for feeding a selected length of chain from a chain supply to said punching means including a drive sprocket engaging the chain and defining an anvil for said punching means; and cutting control means connected to said feeding and punching means for effecting alternate operation thereof. 9. The apparatus of claim 8, comprising: pre-tensioning means interposed between said feeding means and the chain supply for pre-stressing the chain as it is fed for cutting. 10. The apparatus of claim 8, wherein said feeding means comprises:

a motor connected to said sprocket and connected to and operated by said cutting control means. 11. The apparatus of claim 10, wherein said punching means comprises:

a reciprocating punch disposed adjacent said sprocket and including an extension means; and switch means connected to said cutting control means and operated by said extension means to prevent operation of said motor during a punching operation.

12. The apparatus according to claim 11, wherein said punching means further comprises:

means extending from said punch and engaging said sprocket between adjacent teeth threrof to accurately position the chain relative said punch.

13. The apparatus according to claim 12, wherein:

said extension means and said means extending from said punch are both defined by a single pin extending from said punching means.

14. The apparatus of claim 10, wherein said feeding means further comprises:

means resiliently mounting said sprocket for movement a predetermined distance along its axis of rotation.

15. The apparatus of claim 10, comprising:

means connected to said cutting control means and coupled to the chain to detect exhaustion of chain from the supply and responsive to cause said control means to turn off said motor.

16. Chain cutting apparatus comprising:

a frame;

means for rotatably mounting a supply reel of chain on said frame to be cut into shorter lengths;

a cutting station on said frame including a punch for punching at least one pin from a selected connecting link a distance sufficient to separate the chain,

a sprocket located at said cutting station for receiving the chain in engagement therewith and serving as an anvil,

drive means for rotating said sprocket to feed chain from the supply reel and position the selected connecting link opposite said punch, and

means extending from said punch for engaging the 10 sprocket between adjacent teeth thereof to align the selected connecting link and said punch; and

means for alternately and cyclically operating said drive means and said punch to feed and cut the chain.

17. Apparatus for mounting a sprocket which is to feed chain thereabout and serve as an anvil in a chain cutting operation, comprising:

a shaft having the sprocket mounted near one end thereof and adapted to receive a rotary force at the other end thereof;

first and second bearing secured to said shaft;

sleeve means disposed about said shaft between and contacting said first and second bearings;

a cylinder mounting said bearings and sleeve means therein for axial movement;

spring means connected to said cylinder urging said second bearing in the direction toward said sprocket; and

stop means on said housing for limiting axial movement to a predetermined distance.

18. In apparatus for mounting a sprocket which is to have a chain entrained thereabout and serve as an anvil receiving a force parallel to its axis in a chain cutting operation, the sprocket carried on a shaft engaged by bearings in a housing, the improvement comprising:

means mounting said sprocket for movement in the axial direction; and

means including said housing for limiting the axial movement of said sprocket during the cutting operation to relieve the thrust from the bearings. 

